Officials from the Institute of Medicine, which issued the report last week at the request of Congress, said the departments need a better handle on what treatments work.

“All of the services have some type of PTSD treatment program, but no single source within DOD or any of the service branches maintains a complete listing of such programs, tracks the development of new and emerging programs, or has appropriate resources in place to direct servicemembers to programs that may best meet their individual needs,” the report says.

The findings come as military and veterans officials struggle with the effects of more than a decade of war and prepare for the anticipated flood of mental health cases on the horizon.

Medical studies have shown that as many as one-fifth of the 2.6 million troops who served in Iraq and Afghanistan may develop post-traumatic stress disorder. The Institute of Medicine study noted that only slightly more than half of those diagnosed with PTSD actually received treatment for it, either because of problems with access to care or due to perceived stigma associated with the diagnosis.

More than 476,000 veterans received treatment for post-traumatic stress disorder in VA medical centers and clinics in fiscal 2011.

The Institute of Medicine report praised VA and military leaders for a 2010 joint guidance on diagnosis and care of PTSD patients, but noted that neither department tracks whether their providers actually follow those guidelines.

The report says that neither the DOD or VA has adequately explored innovative approaches such as acupuncture and alternative medicines. It also recommends PTSD screening once a year for all troops, mirroring monitoring currently done on at-risk veterans. Researchers said both departments need to develop better baselines for success of their programs, to help craft future treatments.

“Screening for PTSD is ineffective unless there is adequate follow-up to confirm or refuse a positive screen and [there is] adequate capability to provide appropriate treatment,” the report stated.

In separate statements, Pentagon and VA officials did not address the issue of tracking treatment success rates, but said their departments have worked closely to find solutions to the PTSD problems. Both also said they recognize the need for continued improvements.

VA officials have promised to hire 1,900 new mental health specialists and staffers this year to deal with lengthy wait times for veterans seeking treatment for illnesses like PTSD.

Last month, at a suicide prevention conference, Defense Secretary Leon Panetta said he wanted the Pentagon to be a “game-changing innovator” on issues of mental health, to benefit both military personnel and society at large.